Metal Supported Powder Catalyst Matrix and Processes for Multiphase Chemical Reactions

ABSTRACT

A catalytic membrane composite that includes porous supported catalyst particles durably enmeshed in a porous fibrillated polymer membrane is provided. The porous fibrillated polymer membrane may be manipulated to take the form of a tube, disc, or diced tape and used in multiphase reaction systems. The supported catalyst particles are composed of at least one finely divided metal catalyst dispersed on a porous support substrate. High catalytic activity is gained by the effective fine dispersion of the finely divided metal catalyst such that the metal catalyst covers the support substrate and/or is interspersed in the pores of the support substrate. In some embodiments, the catalytic membrane composite may be introduced to a stirred tank autoclave reactor system, a continuous flow reactor system, or a Parr Shaker reaction system and used to effect the catalytic reaction.

FIELD

The present disclosure relates generally to multiphase chemicalreactions, and more specifically, to a porous fibrillated polymermembrane that includes supported catalyst particles durably enmeshedwithin a porous fibrillated polymer membrane for use in multiphasereaction systems.

BACKGROUND

Multiphase chemical reaction systems and processes utilizing powderedcatalysts as the solid phase are known in the art. However, three phasegas-liquid-solid reactions present some difficult problems. Onedifficulty is that of obtaining substantially uniform dispersion ormixing of gas and liquid with the solid for reaction. Sometimes, whenaffecting these reactions, gas and liquid are introduced mixed butseparate or de-mix before reaching the solid catalyst surface. As aresult, side reactions often occur causing by-product buildup andpossibly, dangerous conditions. Poor conversion is another aspect ofimproper mixing. Two phase catalytic reactions are also challenging forsolid catalyst mixing.

The most common current solution to the problems associated withmultiphase chemical reactions is to slurry a finely divided powderedcatalyst in the liquid phase using a shaft driven impeller mixer as itprovides for easy mixing and high distribution of catalyst surface areaover the liquid volume. However, these finely divided powdered catalystsoften require extensive operator handling during reactor charging andduring filtration to separate the catalyst and products after reaction.Additionally, due to their fine size, they are prone to transfer lossesas they stick to surfaces and in crevices at seals within the reactor.Catalyst remaining in the reactor can also lead to process safetyconcerns. For example, the remaining catalyst may become dry and cause afire or explosion. Further, the transfer loss of the powdered catalystresults in inferior net productivity. Operability challenges are alsopresent with the use of powdered catalysts, as extensive carefuloperator handling is required to prevent ignition of dry catalyst powderon reactor charging.

SUMMARY

One embodiment relates to a reaction system for multiphase reactionshaving at least three phases where the reaction system includes (1) astirred tank reaction vessel including a rotatable impeller shaft havingthereon at least one impeller blade where the rotatable impeller shaftis rotatably affixed to a catalytic article, (2) a liquid phaseincluding at least one liquid phase reactant, and (3) a gas phasecomprising at least one gas phase reactant. The catalytic articleincludes supported catalyst particles durably enmeshed within the porousfibrillated polymer membrane. The porous fibrillated polymer membranemay be in the form of an immobilized catalyst disc or disc stack. In atleast one embodiment, the disc stack comprises a plurality ofimmobilized catalyst discs with intervening spacers separating theimmobilized catalyst discs. Also, the immobilized catalyst discs havetherein through-holes for circulation of a reaction mixture through thedisc stack. In one exemplary embodiment, the impeller blade is pitched.The reaction system may be configured for hydrogenation. In exemplaryembodiments, the reaction system is a stirred tank autoclave reactorsystem. The porous fibrillated polymer membrane may includepolytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene(ePTFE), modified PTFE, or a PTFE copolymer. Further, the catalyticarticle is not configured as a contactor. In an alternate embodiment,the porous fibrillated polymer membrane be in the form of diced tape.

Another embodiment relates to a continuous flow reaction system formultiphase reactions having at least three phases where the reactionsystem includes (1) a catalytic article including a porous fibrillatedpolymer membrane that includes supported catalyst particles durablyenmeshed within the porous fibrillated polymer membrane, (2) a liquidphase comprising at least one liquid phase reactant, (3) a gas phasecomprising at least one gas phase reactant, and (4) a reaction vesselconfigured for continuous flow of the liquid phase reactant and the gasphase reactant across and through the catalytic article. The catalyticarticle may be in the form of a tube or a plurality of tubes bundled ina tubular array. In an alternate embodiment, the catalytic article maybe in the form of diced tape. In at least one embodiment, the reactionsystem is configured for hydrogenation. The porous fibrillated polymermembrane may include polytetrafluoroethylene (PTFE), expandedpolytetrafluoroethylene (ePTFE), modified PTFE, or a PTFE copolymer.Additionally, the porous fibrillated has a porosity from about 30% toabout 95%. Further, the catalytic article is not configured as acontactor.

Yet another embodiment relates to a continuous flow reaction system formultiphase reactions having at least three phases where the reactionsystem includes (1) a catalytic article including a porous fibrillatedpolymer membrane that includes supported catalyst particles durablyenmeshed within the porous fibrillated polymer membrane where thecatalytic article is in the form of diced tape, (2) a reaction mixtureincluding a liquid phase having at least one reactant and a gas phasehaving at least one additional reactant, (3) a reaction vesselcontaining the catalytic article and reaction mixture. The reactionmixture has free access to move through and around the catalyticparticles to affect a hydrogenation reaction. The porous fibrillatedpolymer membrane may include polytetrafluoroethylene (PTFE), expandedpolytetrafluoroethylene (ePTFE), modified PTFE, or a PTFE copolymer. Theporous fibrillated polymer membrane is insoluble to reactants andproducts in the multiphase chemical reaction. Further, the catalyticarticle is not configured as a contactor.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this specification, illustrate embodiments, and together withthe description serve to explain the principles of the disclosure.

FIG. 1 is a scanning electron micrograph (SEM) of an exemplary supportedcatalyst particle with a finely divided metal on its surface inaccordance with at least one embodiment;

FIG. 2 is an exploded view of a stack of discs interspaced with a spacermaterial positioned between two metal plates in accordance with at leastone embodiment;

FIG. 3A is a schematic illustration of an autoclave reactor containing adisc stack in accordance with at least one embodiment;

FIG. 3B is a schematic illustration of a stack of discs interspaced witha spacer material positioned on an impeller shaft in accordance with atleast one embodiment;

FIG. 3C is a schematic illustration of an autoclave reactor containingdiced tape in accordance with at least one embodiment;

FIG. 4 is an image depicting tubes formed from a porous fibrillatedpolymer membrane in a tubular array in accordance with at least oneembodiment;

FIG. 5A is a schematic illustration of a top view of the tubesimmobilized in a reactor in accordance with least one embodiment;

FIG. 5B is a schematic illustration of a reaction system including thereactor shown in FIG. 5A in accordance with least one embodiment;

FIG. 6 is a schematic illustration of a continuous loop reactorutilizing a tubular array in accordance with least one embodiment;

FIG. 7 is a schematic illustration of a Parr Shaker Reactor using dicedtape containing supported catalyst particles in accordance with at leastone embodiment,

FIG. 8 is a graphical illustration of catalyst removal filtration aftermultiphase hydrogenation in a stirred autoclave reactor in accordancewith at least one embodiment;

FIG. 9 is a graphical illustration of the change in pressure duringautoclave reactions in accordance with at least one embodiment;

FIG. 10 is a graphical illustration of the relative productivity ofbatches 2, 3, and 4 of multiphase hydrogenation of hydrogen ands-limonene per moles of Pd metal charge in a stirred autoclave reactorin accordance with at least one embodiment; and

FIG. 11 is a schematic illustration of a continuous loop reactor usingdiced tape in accordance with least one embodiment.

DETAILED DESCRIPTION

Persons skilled in the art will readily appreciate that various aspectsof the present disclosure can be realized by any number of methods andapparatus configured to perform the intended functions. It should alsobe noted that the accompanying drawing figures referred to herein arenot necessarily drawn to scale, but may be exaggerated to illustratevarious aspects of the present disclosure, and in that regard, thedrawing figures should not be construed as limiting. As used herein, theterms “porous supported catalyst particle” and “supported catalystparticle” may be used interchangeably herein. Also, the terms“immobilized catalyst disc” and “disc” may be used interchangeablyherein.

The present disclosure is directed to a catalytic membrane compositethat comprises porous supported catalyst particles durably enmeshed in aporous fibrillated polymer membrane. It is to be noted that thesupported catalyst particles may alternatively be non-porous orsubstantially non-porous. The fibrillated polymer membrane may bemanipulated to take the form of a tube, disc, or diced tape and used inmultiphase reaction systems. The supported catalyst particles arecomposed of at least one finely divided metal catalyst dispersed on aporous support substrate. The catalytic membrane composite may be usedin multiphase chemical reactions in a variety of different classesincluding, but not limited to, hydrogenations, hydrogenolysis, nitrogroup reductions, hydrodehalogenations, hydrodesulphurization,hydrocracking, hydrodenitration, and deoxygenation. The catalyticmembrane composite may be introduced to a stirred tank autoclave reactorsystem, a continuous flow reactor, or a Parr Shaker Reactor and used toeffect the catalytic reaction. In the instant disclosure, the catalyticarticle is not configured as a contactor (i.e., the porous fibrillatedpolymer membrane is not used to separate the phases of the reaction.)

The porous supported catalyst particles may be also used in preparationof agrochemical, industrial chemicals, specialty chemicals, flavors,fragrances, food stuffs, fuels, materials for use in organic lightemitting diodes, polymers for lithography, active pharmaceuticalingredients, or intermediates to such active pharmaceuticals. In thespace of chemicals, the porous supported catalyst particles can be usedin the preparation or modification of analgesics, lipids,anti-inflammatories, statins, cholesterol inhibitors, insulinstimulators, treatments for diabetes, treatments for heart disease, painmedications, metabolites, neurotransmitters, agonists, antivirals,opioids, nucleic acids, enzyme inhibitors, antibiotics, polypeptides,oligonucleotides, alkaloids, glycosides, lipids, non-ribosomal peptides,phenazines, natural phenols (including flavonoids), polyketides, colorbodies, polymers, terpenes, steroids, tetrapyrroles, adjuvants,polysaccharides, herbicides, pesticides, enzymes, antibodies, and otherchemicals with specific commercial applications.

The supported catalyst particles are formed of at least one finelydivided catalytic metal that is supported on and/or within a supportsubstrate. As used herein, the term “finely divided” is meant to denotecatalytic metals that are present in particles or grains that have anaverage particle size less than ten microns in diameter. In someembodiments, the finely divided catalytic metal has a range from about 3µm to about 0.1 nm, from about 3 µm to about 5 nm in diameter, or fromabout 1 µm to about 1 nm in diameter. Catalytic metals suitable forincorporation onto the support substrate include elements selected fromGroup Vb, Group VIb, Group VIIb, Group VIIIb, and Group lb metals of theperiodic table. Non-limiting examples of metal catalysts include cobalt,nickel, Raney-type metals or sponge nickel, palladium, platinum, copper,cobalt, rhodium, ruthenium, and rhenium. In some embodiments, mixturesof catalytic metals (e.g., palladium and nickel or copper chromiumoxides) are dispersed onto the support substrate.

The finely divided metal catalysts may be dispersed onto and/or into thesupport substrate by known and optimized processes described in the artincluding, but not limited to, precipitation, plating, atomic layerdeposition, and molecular layer depositions. Incipient wetness from asalt solution of the catalytic metal is one non-limiting example of amethod for incorporating a catalytic metal on the substrate particle.The metal catalyst loadings onto the support substrate may range fromabout 0.1 to about 25% by weight, from about 0.5 to about 15% by weight,or from about 1 to about 10% by weight of the supported catalystparticle. The support substrate may comprise from about 75% to about99.9%, from about 85% to about 99.5%, or from about 90% to 99% by weightof the supported catalyst particle. High catalytic activity is gained bythe effective fine dispersion of the finely divided metal catalyst suchthat the metal catalyst covers the support substrate and/or isinterspersed in the pores of the support substrate.

The support substrate is not particularly limiting so long as it doesnot affect the multiphase catalytic reaction in which it is used. Inexemplary embodiments, the support substrate is porous. Examples ofmaterials for use as the support substrate include, but are not limitedto, metals, metal oxides (e.g., aluminum oxide), silica, clays,diatomaceous earth (e.g., kieselguhr), zeolites (e.g., X, Y, A, andZSM), carbon, and activated carbon. In at least one embodiment, thesupport substrate is spherical in shape and has a diameter in the rangefrom about 10 µm to about 300 µm, from about 10 µm to about 150 µm, orfrom about 10 µm to about 30 µm; or from about 0.5 µm to about 10, fromabout 0.5 µm to 5 µm, from about 0.5 µm to about 4 µm, from about 0.5 µmto about 3 µm, from about 0.5 µm to about 2 µm, or from about 0.5 µm to1.0 µm. It is to be appreciated that the term support substrate is notmeant to be limiting, and particles, flakes, fibers, nanotubes,nanoparticles, platelets, and powders are considered to be within thepurview of the present disclosure. FIG. 1 is a scanning electronmicrograph (SEM) of an exemplary spherical supported substrate with afinely divided metal on its surface.

As discussed above, the supported catalyst particles are durablyenmeshed in an expanded polymer matrix. As used herein, the phrase“durably enmeshed” is meant to describe a supported catalyst particlethat is non-covalently immobilized within the fibrillated microstructureof the polymer membrane. No separate binder is present to fix thesupported catalyst particles in the membrane. Additionally, thesupported catalyst particle is located throughout the thickness of thefibrillated polymer membrane. The porous nature of the fibrillatedpolymer membrane allows free access to the supported catalyst particles(solid phase) by the liquid/gas mixture (liquid/gas phase).Additionally, the porous fibrillated membrane may have a pore size fromabout 0.1 µm to about 355 µm (or higher), from about 0.1 µm to about 200µm, about 0.1 µm to about 100 µm, or from about 0.1 µm to about 40 µm asdetermined by mercury poroisometry.

The polymer forming the fibrillated polymer membrane is a solvent inertor solvent resistant polymer. In particular, the polymer may be bothinsoluble and inert to the reactants and products of the multiphasechemical reaction in which it is used. The fibrillated polymer membranemay comprise polytetrafluoroethylene (PTFE), expandedpolytetrafluoroethylene (ePTFE), poly(ethylene-co-tetrafluoroethylene)(ETFE), ultrahigh molecular weight polyethylene (UHMWPE), polyethylene,polyparaxylene (PPX), polylactic acid (PLLA), polyethylene (PE),expanded polyethylene (ePE), and any combination or blend thereof. It isto be understood that throughout this disclosure, the term “PTFE” ismeant to include not only polytetrafluoroethylene, but also expandedPTFE, modified PTFE, expanded modified PTFE, and expanded copolymers ofPTFE, such as, for example, described in U.S. Pat. No. 5,708,044 toBranca, U.S. Pat. No. 6,541,589 to Baillie, U.S. Pat. No. 7,531,611 toSabol etal., U.S. Pat. No. 8,637,144 to Ford, and U.S. Pat. No.9,139,669 to Xu et al. The porous fibrillated polymer membrane may alsobe formed of one or more monomers of tetrafluoroethylene, ethylene,p-xylene, and lactic acid. In at least one embodiment, the porousfibrillated polymer membrane is comprised of solvent inert sub-micronfibers of an expanded fluoropolymer.

In some embodiments, the fibrillated polymer membrane is apolytetrafluoroethylene (PTFE) membrane or an expandedpolytetrafluoroethylene (ePTFE) membrane having a node and fibrilmicrostructure. The fibrils of the PTFE particles interconnect withother PTFE fibrils and/or to nodes to form a net within and around thesupported catalyst particles, effectively immobilizing them. Therefore,in one non-limiting embodiment, the fibrillated polymer membrane may beformed of a network of PTFE fibrils immobilizing and enmeshing thesupported catalyst particles within the fibrillated microstructure.

The porous fibrillated polymer membrane may be formed by blendingfibrillating polymer particles with the supported catalyst particles ina manner such as is generally taught in U.S Publication No. 2005/0057888to Mitchell, et al., U.S Publication No. 2010/0119699 to Zhong, et al.,U.S. Pat. No. 5,849,235 to Sassa, et al., U.S. Pat. No. 6,218,000 toRudolf, et al., or U.S. Pat. No. 4,985,296 to Mortimer, Jr., followed byuniaxial or biaxial expansion. As used herein, the term “fibrillating”refers to the ability of the fibrillating polymer to form a node andfibril microstructure. The mixing may be accomplished, for example, bywet or dry mixing, by dispersion, or by coagulation. Time andtemperatures at which the mixing occurs varies with particle size,material used, amount of particles being co-mixed, etc. and are easilyidentified by those of skill in the art. The uniaxial or biaxialexpansion may be in a continuous or batch processes known in those ofskill in the art and as generally described in U.S. Pat. No. 3,953,566to Gore and U.S. Pat. No. 4,478,665 to Hubis.

The porous fibrillated polymer membrane may be utilized in multiphasecatalyzed reactions. There are numerous categories of multiphasecatalyzed reactions including those with gas plus liquid reactants, gasplus liquid plus a second immiscible liquid phase reactants, liquid plusimmiscible/liquid phase reactants, or gas plus condensed liquid vaporphase reactants and various other combinations with at least twodistinct phases of matter exist for such reactants that can be used withthe porous fibrillated polymer membrane. These reactions may be carriedout where the porous fibrillated polymer membrane is located, forexample, in a stirred tank autoclave reactor system, a continuous loopreactor, or a Parr Shaker Reactor as described herein. In onenon-limiting embodiment, the porous fibrillated polymer membrane may beused in the hydrogenation of a solvated compound in a liquid or acompound in a mixture of immiscible liquids. Non-limiting examples ofsolvents that may be employed in three-phase reactions include loweralcohols (e.g., methanol and ethanol), tetrahydrofuran, and glycols(e.g., ethylene glycol and diethylene glycol). The solvent may bepresent in the hydrogenation reaction in an amount from about 1% toabout 99%, from about 1% to about 75%, or from about 1% to about 50% byweight of the charge.

In one exemplary embodiment, the porous fibrillated polymer membrane maybe cut into immobilized catalyst discs 210 and stacked into disc stack200 with intervening spacers 220 as shown in FIG. 2 for use in a stirredtank reaction vessel. The intervening spacers 220 may be washers or ascrim or plastic material (e.g., polyvinylidene fluoride (PVDF) scrim)The disc stack 200 may be positioned between a top alignment plate 230and a bottom alignment plate 240 that are mechanically interconnected,such as by screws or bolts, to securely hold the disc stack 200together.

Turning to FIG. 3A, a schematic illustration of an autoclave reactor 300(e.g. a stirred tank reaction vessel) containing the disc stack 200 maybe seen. The autoclave reactor 300 may include a lid 310 removablyaffixed to an autoclave tank reservoir 315. The tank reservoir isjacketed by a heating mantle 320. The lid 310 includes an inlet 330 fora temperature probe and an inlet 340 to introduce hydrogen gas into thereaction system. A cooling loop 350 may be present in the autoclavetank. The disc stack 200 is mounted on a rotatable impeller shaft 360having thereon an impeller blade 370 and inserted into the reactionmixture 390. It is to be appreciated that the impeller blade 370 may bepositioned on the impeller shaft 360 at any location along the shaft 360so long as the impeller blade 370 is rotatable within the tank 315 andstirs the reaction mixture 390 through the disc stack 200. In addition,more than one impeller blade may be positioned on the impeller shaft360, either above, below, or above and below the disc stack 200. Theimpeller blade 370 depicted in FIG. 3A is not meant to be limiting, andthe impeller blade 370 may be formed of one or more blades, spiralstructures, or be an impeller turbine.

FIG. 3B schematically depicts an enlarged view of the disc stack 200 onthe impeller shaft 360. As shown, the impeller shaft 360 extends throughthe center of the disc stack 200. Through-holes 280 extend through theplane of the catalytic discs 210 and intervening spacers 220 and permitcirculation through the disc stack 200. The through-holes 280 alsoextend through the first alignment plate 230 and the second alignmentplate 240. It is to be appreciated that the catalytic discs 210 andintervening spacers 220 may be positioned such that the through-holes280 in discs 210 and spacers 220 align with each other to form holes 290through the entire disc stack 200. Any number of through-holes may belocated within the catalytic discs 210 and the intervening spacers 220.The alternating stack of immobilized catalyst discs 210 and spacers 220is positioned between the first alignment plate 230 and the secondalignment plate 240, and is held together by bolts 260 and screws 270.

The reaction mixture 390 includes the liquid/gas phase of thethree-phase catalytic reaction. The impeller shaft 360 and the impellerblade 370 may be driven by a motor 380. To effect a catalytic reaction,the impeller blade 370 with the attached disc stack 200 are rotatedwithin the autoclave tank 315, effecting a mixing motion within the tank315. The disc stack 200 containing the immobilized catalyst discs 210rotate with the shaft 360 such that reaction mixture 390 is recirculatedbetween the discs 210 and through the autoclave tank 315. Due to theporous structure of the fibrillated polymer membrane, the reactant(s) inthe reaction mixture 390 are able to move through the immobilizedcatalyst discs 210 and react with the finely divided catalyst on thesupported catalyst particles. Unlike reaction systems that use bindersand other polymers, the immobilized catalyst discs 210 do not block thesurfaces of the supported catalyst particles, allowing movement of thereactant(s) through and around the discs 210.

In an alternate embodiment depicted generally in FIG. 3C, the porousfibrillated polymer membrane may be cut or diced, such as into ageometric shape (e.g. a square, rectangle, circle, triangle, etc.) whichis referred to herein as “diced tape”. To effect a catalytic reaction,the impeller blade 370 effects a mixing motion within the tank 315,thereby causing the diced tape 395 to move within the reaction mixture390. Due to the porous structure of the fibrillated polymer membrane,the reactant(s) in the reaction mixture 390 are able to move through andaround the diced tape 395 and react with the finely divided catalyst onthe supported catalyst particles.

In another embodiment, the porous fibrillated polymer membrane may beslit or cut into strips and wound around a tubular support member at adesired pitch, e.g. from about 40° to about 60°. Non-limiting examplesof suitable tubular support members include stainless steel springs,braided wire, extruded porous polymeric tubes, perforated metal tubes,and plastic or metal static mixers. Depending on the desired length andthe length of the wrapped tubular support member, the wrapped tubularsupport member may be cut to the desired length to form tubes. As shownschematically in FIG. 4 , the tubes 410 may be bundled together into atubular array 400 for insertion into a reactor. In one embodiment, thetubes 410 are bundled together with a plastic film 420.

Turning to FIGS. 5A and 5B, these tubes 410 (or the wrapped tubularsupport members) may be installed into a reactor assembly 500 such thatthey are immobilized. As shown in FIG. 5B, the tubular array 400 may beinserted into a glass tube 510 (e.g., sight glass tube) and sealed ateach end thereof with sanitary gaskets 530. The gaskets 530 may beformed of rubber, such as Viton™ sanitary gaskets. The glass tube 510containing the tubular array 400 may be mounted between an upstreamsanitary connector 540 and a downstream sanitary connector 550. Thesanitary connectors 540, 550 may be held together by bolts 560 and nuts565. A perforated plate 580 may be placed in the upstream sanitaryconnector 540 and the tube 545 of the upstream sanitary connector 540may be filled with glass beads 570 for flow distribution.

To effect a catalytic reaction, the reactor assembly 500 may be fluidlyconnected to a container containing a reaction mix containing theliquid/gas phase. The reaction mixture may be pumped or otherwise fedinto the reaction assembly 500 through the perforated plate 580 andglass beads 570. Both the perforated plate 580 and the glass beads 570distribute the flow of the reaction mixture so that it is evenly orsubstantially evenly distributed through the tubes 410. The reactionmixture is passed through the tubes 410 located in the reactor assembly500, where the liquid/gas phase in the reaction mixture is contactedwith the supported catalyst particles (solid phase) enmeshed in theporous fibrillated polymer membrane forming the tubes 410. In oneembodiment, the reactor assembly 500 may be inserted into a continuousflow reaction system, such as the continuous flow reaction system 600depicted generally in FIG. 6 and discussed in detail in the sectionbelow entitled “Continuous Loop Reactions in a Packed Tubular Array”.Due to the porous structure of the fibrillated polymer membrane, thereactant(s) in the reaction mixture are freely able to move through thetubes 410 in the reactor assembly 500 and react with the finely dividedcatalyst on the surface of the supported catalyst particles. Inaddition, the distribution of the supported catalyst particles withinthe porous fibrillated polymer membranes allow for uniform catalystactivity and distribution over the length of the tubes 410.Additionally, the reaction mixture may flow through the interstitialspaces between the tubes 410 and not only through the lumen of the tubes410. In addition, the reactor assembly 500 demonstrates anadvantageously lower pressure drop in comparison to conventional packedbeds of powder or pellets.

In yet another embodiment, a porous fibrillated polymer membrane may becut or diced, such as into a geometric shape (e.g. a square orrectangle) which is referred to herein as “diced tape”. The diced tapemay be utilized in a Parr Shaker Reactor, such as is schematicallydepicted in FIG. 7 . As shown, a reaction mixture 710 containing theliquid/gas phase of the three-phase catalytic reaction is placed into atank 730 together with the diced tape 720 containing the supported metalcatalysts. The tank 730 is then pressurized with a gas 740 (e.g.,hydrogen). A pressure gauge 760 may be used to monitor the internalpressure of the tank 730. A heating jacket 750 provides heat to the tank730 for the reaction process. To affect a catalytic reaction, the tank730 is shaken by a shaking device (not illustrated), thereby creating amixing motion within the tank 730. As a result, the diced tape 720 iscirculated within the reaction mixture 710. Due to the porous structureof the fibrillated polymer membrane, the reactant(s) in the reactionmixture 710 have free access to move through and around the diced tape720 and react with the finely divided catalyst on the surface of thesupported catalyst particles.

In a further embodiment, the porous fibrillated polymer membrane in theform of diced tape may be used in a continuous loop reactor such as isillustrated in FIG. 11 . The continuous loop reactor 800 includes a gasmetering pump 810, a liquid metering pump 820, a diced tape meteringmember 870, and a pump 830 to circulate the reaction mixture 860 aroundthe looped reactor 800. The gas reactant(s) and liquid reactant(s) arefed into the reactor tank 880 via the gas and liquid metering pumps 810,820, respectively, to form the reaction mixture 860. The diced tape 850is introduced into the reaction mixture 860 via the diced tape meteringmember 870. To effect a catalytic reaction, the pump 830 effects acircular motion of the reaction mixture 860 within the tank 880, therebycausing the diced tape 850 to move within the reaction mixture 860. Dueto the porous structure of the fibrillated polymer membrane, thereactant(s) in the reaction mixture 860 are able to move through andaround the diced tape 859 and react with the finely divided catalyst onthe supported catalyst particles.

In the embodiments described above, the porous fibrillated polymermembrane effectively distributes the supported metal catalyststhroughout the membrane, in both the length and thickness directions. Inaddition, the porous nature of the fibrillated polymer membrane allowsfor efficient and reliable transport of multiphase reactants andproducts to and from the catalyst surface. Further, catalyst loss isminimized as a result of the supported catalyst particles being durablyenmeshed within the fibrils of the porous fibrillated polymer membrane.

TEST METHODS

It should be understood that although certain methods and equipment aredescribed below, other methods or equipment determined suitable by oneof ordinary skill in the art may be alternatively utilized.

Formation of Disc Stack

Porous fibrillated polymer membranes described in the Examples were diecut into discs with 9 holes: 8 holes with ¼ inch diameter and one centerhole for the shaft having a 0.380 inch diameter. These immobilizedcatalyst discs were then assembled into a disc stack using bolts in theouter four holes for mounting onto stainless steel alignment platesDiscs were stacked and spaced apart by washers and similarly die cutdisks of a polyvinylidene fluoride (PVDF) expanded plastic mesh (DexmetCorporation, Wallingford, Connecticut). The PVDF mesh spacers had athickness of 0.020“ (~ 0.051 cm), a strand width of 0.010“ (~ 0.025 cm),and diamond shaped openings with a (LWD) long width dimension of 0.158“(~ 0.401 cm) and a short width dimension (SWD) of 0.125“ (~ 0.318 cm).The immobilized catalyst discs and PVDF mesh spacers were stacked usingwashers with a spacing of 0.125“ (~ 0.318 cm) between discs and the PVDFmesh spacers. A separation of 0.125“ (~ 0.318 cm) was also kept betweenthe top and bottom discs and the respective stainless steel alignmentplate. The disc stack and stainless steel alignment plates were boltedtogether using screws and nuts. A set screw was then used to secure thedisc stack to the impeller shaft in the reactor apparatus (e.g.,autoclave reactor or stirred reactor) such that the disc stack wouldturn with the impeller shaft of the reactor apparatus. Thus theimmobilized catalyst discs would rotate with the impeller shaft suchthat reaction mixture (e.g., liquid/gas phase) would be recirculatedbetween the discs and through the tank of the reactor.

Parr Shaker Reaction and Reactor Description

A Model 3910 Parr hydrogenation apparatus (Parr Instrument Company,Illinois), also known as a “Parr shaker” was used. Reactions werecarried out in neoprene stoppered 500-mL Parr glass bottles. The bottleswere jacketed with a heating mantle and metal guard commerciallyavailable from Parr Instrument Company. To conduct the reaction, theglass bottles were charged with either 100 mL of the EAQ workingsolution or 100 mL of s-limonene 96% purity from Sigma Aldrich. Catalystwas then added in the amount noted in the Example. The bottle was cappedand mounted in the Parr shaker with the neoprene stopper through which agas inlet line and thermocouple immersed in the solvent were added. Thebottle was then purged of air by pressurization with hydrogen to 50 psi(~ 0.35 MPa) and vented repeatedly.

After purge, the bottle was pressurized to 5 psi (~ 0.035 MPa) withhydrogen, the Parr shaker was started, and the temperature control setpoint was turned on and set to 50° C. (EAQ working solution) or 25° C.(limonene). After coming up to temperature (5-10 minutes), the shakingwas stopped, the bottle was pressurized to 50 psi (~ 0.35 MPa), and thepressure reservoir valve was closed so that the system included thebottle and gas line to the pressure gauge with approximately 420 mL ofhydrogen head space. The shaker was then started at 4 hertz (Hz)frequency and the pressure inside the bottle recorded and monitored for10 minutes as described in the respective example. Hydrogenationreaction progress was then assessed based on pressure decrease in thereactor.

Stirred Tank Autoclave Reactions and Apparatus

For tests using conventional supported catalyst slurry powder and discstacks with supported catalyst particles immobilized in porousfibrillated membranes, the same 1 gallon (~ 3.79 Liters) autoclave tankwas used. The reactor was an Autoclave Engineers 1 gallon (~ 3.79Liters) HASTELLOY® C (a corrosion resistant alloy composed of nickel,molybdenum, chromium, and iron) vessel, model number N6657HC, rated at2200 psi (~15.17 MPa). The vessel uses a magnetic coupling to thecentral drive shaft for a bearing attached impeller inside the reactor.The magnetic coupler is attached to an external electric motor or an airmotor via a belt drive as noted in the Example. The stir speed was setat 300 revolutions per minute (rpm) or 350 rpm as noted in the Example.

For all experiments, the reactor was charged with 1 L of EAQ workingsolution prepared as described below. Catalyst was added in the amountnoted in the Example, and the reactor was purged to remove air usingsequential pressurization / depressurization while stirring withhydrogen at room temperature. The reactor was equipped with an electricheating jacket monitored by a thermocouple through a thermowell in thevessel lid and controlled via a proportional integral derivative (PID)tuned electronic temperature controller. The temperature control was setto the noted temperature set forth in the Example. The reactor wasequilibrated with charge at this temperature for one hour within +/-2°C. at 50 psi (~0.35 MPa) of hydrogen without stirring prior to startingthe reaction unless otherwise noted. At the start of the reaction, thetemperature controller for the heating element was turned off. Pressurein the reactor was monitored directly from a digital pressure gaugemounted in the reactor lid.

To initiate a reaction run, the reactor was sealed and pressurized tothe noted set pressure with hydrogen, for example, 50 psi (~0.35 MPa) or200 psi (~1.38 MPa), respectively. Stirring was initiated, and thetemperature controller for heating was turned off. The pressure wasrecorded at set intervals for the duration of the reaction as noted inthe Examples.

Hydrogenation reaction progress was then assessed based on pressuredecrease in the reactor. The reactor was equipped with a tubular watercooling loop (though it was not used for cooling) and was filled withhydrogen during the experimental runs. No baffles were inserted forthese experiments, though the immersed water cooling loop provided somebaffling in the experiments conducted. The action of the turbineimpeller created a low pressure zone at the point of agitation. Thatrotation of the turbine causes the hydrogen to break into finely dividedbubbles and cause dissolution of hydrogen in the respective liquidworking solution. In doing so, a frothy mixture was created which washelpful in bringing both reactant phases to the catalyst surface. Inaddition, the rotating action of the impeller lead to uniform suspensionof powdered catalyst throughout the liquid in examples where thestructured catalyst particle was present in a free form.

After each test and between runs, the reactor was depressurized, theworking solution removed via draining, the reactor was subjected tomultiple rinse and drain steps using a volatile co-solvent for the EAQworking solution until all surfaces were visibly clean and free fromcatalyst particles. The reactor was then dried and charged for the nextreaction as described in the Examples. For sequential experiments usingthe same catalyst charge, the catalyst was vacuum filtered from theworking solution on Whatman number 2 filter paper (Thermo FisherScientific) to recover the powdered catalyst. The catalyst was thencarefully scraped off the filter paper with care to avoid damaging thefilter, and put back into the reactor for the next charge.

Continuous Loop Reactions in a Packed Tubular Array

To further demonstrate the breadth of the instant invention of apowdered catalyst comprising metal dispersed on a porous supportparticle where the support particle is immobilized in a fibrillaryporous matrix for multiphase chemical reactions beyond batch conditions,the following experimental apparatus for continuous flow reactions wasused.

A porous fibrillated polymer membrane having a porosity from about 30%to about 95% was slit to a width of 0.25 inches (~0.64 cm) and spiralwrapped at a 52° angle onto a stainless steel stock spring(McMaster-Carr, Robbinsville, NJ, item# 9663K64 - W.B. Jones part# 732;W.B. Jones Spring Company, Wilder, KY) previously stretched to ~150% ofits original length and heat set at total length of 15 inches (~ 38.1cm) and nominal outer diameter of 0.096 inches (~0.244 cm). The tubularwrapped spring was tacked in place with a molten plastic film at 5 inch(~ 12.7 cm) intervals and cut into 5 inch (12.7 cm) tubes. Each wrappedtube had (~5 g / 21 tubes or ~0.24 g) grams of membrane.

Twenty one (21) of the tubes were bundled and wrapped tightly togetherwith a plastic film and mounted in a Viton™ sealed sanitary sight glasswith a 6 inch (~15.2 cm) viewable area. The sight glass was mounted intoa continuous flow through reactor using Viton™sanitary gaskets using its1 inch (~2.54 cm) sanitary flange connectors. A sanitary gasket withperforations was placed in the upstream sanitary connector and the tubeof the entrance sanitary flange of the sight glass ahead of the tubulararray was filled with glass beads for flow distribution.

The above-described continuous flow through reactor was mounted in thecircuit schematically depicted in FIG. 6 . The continuous flow throughreactor included gas and liquid metering pumps 610, 620, a back pressurevalve 630, a pressure gauge 635, a 5-liter gas separator flask 640, aliquid sump 650 comprising a 5-liter 3-neck glass round bottom flaskwith a thermocouple and PID controlled heating mantle 660 and magneticstirrer (not illustrated). The separator flask 640 was vented toatmosphere with a glass condenser 670 to prevent evaporation and allowexcess hydrogen to escape into the atmosphere. All circuit plumbing wasdone with ⅜″ (~9.5 mm) fluorinated ethylene propylene (FEP) tubing andstainless steel compression fittings.

To prepare the system, the sump round bottom flask 650 was charged with1.75 L of EAQ working solution and the system was purged with nitrogen.Liquid flow was commenced using the liquid metering pump 620 at 300mL/min. The heating mantle 660 was set to 50° C. and the systemtemperature was equilibrated over an hour. To commence reaction, theliquid metering pump 620 was increased to 600 mL/min and the hydrogengas metering pump 610 was started at 2100 mL per minute, resulting inalternating liquid and gas bubbles being visible in the primary FEPtubing and in spaces between outer tubes in the bundled tube reactor 500itself. The back pressure valve 630 was adjusted to provide for ahydrostatic pressure in the reactor ahead of the valve set to 36 psi (~0.25 MPa). The differential pressure across the reactor was less than0.2 psi (~1.38 kPa).

Reaction was commenced via recirculation and 20 mL samples of workingfluid were withdrawn through a 0.7 µm fiberglass syringe filter afterthe reactor at 15 minute intervals. These samples were then oxidized viabubbling with gentle air flow for 20 minutes. A 5-mL aliquot of eachsample was then shaken with distilled water for 5 minutes to extract thehydrogen peroxide to the water phase. Each water sample was thentitrated using standardized permanganate solutions to quantify theconcentration of H₂O₂.

Mercury Porosimetry Testing

Porosity measurements were carried out on a Micromeritics AutoPore Vmercury porosimeter (Micromeritics, Norcross, Ga., USA), usingMicromeritics MicroActive software version 2.0. Quadruple DistilledVirgin Mercury - 99.9995% purity (Bethlehem Apparatus, Bethlehem, PA)was used as received for tests. Tests used a solid type penetrometerwith a bulb volume of 5 cc and a stem volume of 0.392 cc (SN: 07-0979).Pieces of the composite samples were cut into 1 cm × 2 cm strips andenough of these strips were weighed on an analytical balance to providea total mass of approximately 0.25 g. After noting the mass, the samplepieces were placed in the penetrometer.

The test parameters were as follows: (1) the penetrometer was placedinto the low pressure port on the AutoPore and evacuated to 50 µm Hg,followed by 5 min unrestricted evacuation; (2) the penetrometer was thenfilled with mercury at 0.5 psia (~3.5 kPa) and equilibrated for 10seconds; pressure was subsequently applied to the capillary usingnitrogen in steps up to 30 psia (~0.21 MPa), equilibrating for 10seconds at each step prior to determining the intrusion volume via thestandard capacitance measurement with the penetrometer capillary; (3)the penetrometer was removed from the low pressure port after returningto atmospheric pressure and then weighed to determine the amount ofmercury added; (4) the penetrometer was subsequently placed into thehigh pressure port on the AutoPore and the pressure was again increasedin a series of steps up to approximately 60,000 psia (~ 413.7 MPa)allowing 10 sec at each step to equilibrate prior to intrusion volumemeasurements.

The intrusion volume V at any pressure is determined through acapacitance measurement using the pre-calibrated capillary (i.e., acylindrical capacitor where the outer contact is the metallized coatingon the external surface of the glass capillary, the inner contact is theliquid mercury, and the dielectric is the glass capillary). The totalintrusion volume divided by the sample mass gives the specific intrusionvolume (in mL/g).

The volume occupied by the sample was calculated at the two extremetarget pressures, namely, 0.5 psia (~3.5 kPa) and 60,000 psia (~ 413.7MPa). Since the penetrometer has a known calibrated volume, thedifference between this volume and the mercury volume (determined fromthe mass increase after mercury addition at low pressure and the densityof mercury) yields the volume of the sample including any pores.Dividing the mass of the sample by the volume at this low pressureprovides the bulk density of the sample. At high pressure, where mercuryhas been pushed into the pores by an amount given by the intrusionvolume, the skeletal density can be approximated by dividing the samplemass by the adjusted sample volume (e.g., low pressure volume minustotal intrusion volume).

Total Pore Area

The total pore area reported was determined through a series ofintermediate calculations. First, the diameter of the pores being filledat a given pressure was calculated using the Washburn equation:

$D_{i} = \frac{- 4\gamma\text{c}os\theta}{P_{i}}$

where D_(i) = pore diameter at the i^(th) pressure point, γ = surfacetension, θ = contact angle and P_(i) = pressure. The mean diameter forthe i^(th) point is then taken to be:

Dm_(i) = (D_(i) + D_(i-1))/2

The incremental specific intrusion volume for the i^(th) point wascalculated from the total intrusion volume taken at each point (I_(i)):

li_(i) = l_(i) − l_(i-1)

Finally, the incremental specific pore area for the i^(th) point wascalculated from the incremental intrusion volume and the mean diameterfrom:

Ai_(i) = (4 × li_(i))/Dm_(i)

The total (i.e., cumulative) specific pore area for the i^(th) point wasthen calculated as:

A_(i) = Ai_(i) + Ai_(i-1) + … + Ai_(i).

Bulk Density

The bulk density of the sample is the density of the solid including allopen pores and internal void volume. The bulk density was calculated bydividing the sample mass by the low pressure mercury intrusion volume.Sample mass was determined by weighing on an analytical balance of +/-0.01 mg sensitivity.

Bulk Density = M/(V_(Low Pressure))

Skeletal Density

The skeletal density is the density of a solid calculated by excludingall open pores and internal void volume. The skeletal density wascalculated by dividing the sample mass by the adjusted sample volume(low pressure volume minus total intrusion volume). The sample mass wasdetermined by weighing on an analytical balance of +/- 0.01 mgsensitivity.

Skeletal Density = M/((V_(Low Pressure)) − (V_(High Pressure)))

where V_(Low) _(Pressure) is volume of the sample at 0.5 psia (~3.5 kPa)and V_(High) _(Pressure) is total intrusion volume at 60,000 psia (~413.7 MPa).

Total Porosity

The total porosity within the substrate is simply the void volume of thesample divided by the total volume of the sample. This can be calculatedas:

$\begin{array}{l}{\%\text{Porosity} = 100*\left( {\text{total intrusion volume at 60,000 psia}\left( {\text{\textasciitilde}413.7} \right)} \right)} \\{\left( \left( \text{MPa} \right) \right)/\left( {\text{volume of the sample at 0}\text{.5 psia}\left( {\text{\textasciitilde}3.5\text{kPa}} \right)} \right)}\end{array}$

Thickness

Membrane thickness was measured by placing the membrane between the twoplates of a Kafer FZ1000/30 thickness snap gauge (Käfer MessuhrenfabrikGmbH, Villingen-Schwenningen, Germany). The average of the threemeasurements was used.

TEST MATERIALS Ethyl Anthraquinone (EAQ) Working Solution

The EAQ working solution was prepared by dissolution of 100 g EAQ in asolution of 666 mL trimethyl benzene (TMB) and 333 mL of trioctylphosphate (TOP). Both the EAQ and TMB were acquired from Sigma- Aldrich(St. Louis, MO). The TOP was acquired from TCI Chemical (TCI America,Portland, OR). All three chemicals were reagent grade (>98% purity) andwere used as received without further purification. The EAQ wasdissolved into the TMB/TOP solution slowly in a 6-L master batch withgentle heat supplied via a heating mantle controlled to 40° C. withstirring in a closed glass round bottom flask. The starting EAQ workingsolution was a yellow color.

Separate analytical studies were performed using standard permanganateperoxide titrations to establish that the consumed hydrogen is directlyproportional to production of hydrogenated EAQH₂ on a molar basis forthe Pd/SiAl catalyst employed in the Examples. The consumption ofhydrogen is directly proportional to the change in H₂ hydrogen gaspressure. Since the molar consumption of hydrogen is directlyproportional to the product produced it serves as a direct proxy for themoles of product in calculation of reactivity and productivity metrics.

Limonene Solution

40.8 g of (-)-limonene (Acros Organics, Thermo Fisher Scientific, 96%,CAS 5989-54-8) was dissolved in a total volume of 1000 mL made up ofabsolute ethanol. This solution was used as made for subsequentreactions without further purification. The reaction of limonene withhydrogen proceeds with quantitative yield. Therefore the consumption ofhydrogen is a direct proxy for the molar quantity of methane produced.

EXAMPLES

Unless defined otherwise herein, all technical and scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which this invention belongs. The present inventionis further defined in the following Examples. It should be understoodthat these Examples, while indicating preferred embodiments of theinvention, are given by way of illustration only. From the abovediscussion and these Examples, one skilled in the art can ascertain theessential characteristics of this invention, and without departing fromthe spirit and scope thereof, can make various changes and modificationsof the invention to adapt it to various uses and conditions.

Comparative Example 1

0.225 grams of 2 wt% Pd (0.0045 g Pd metal) on a SiO₂-Al₂O₃ support-Type 429 powdered catalyst from Johnson Matthey (Royston, UnitedKingdom) and 100 mL of EAQ working solution were charged to a 0.5-L Parrglass bottle. Prior to reaction the catalyst was preconditioned toensure any oxidized Pd would be returned to a reduced state byconditioning in the working solution for 1 hour at 55° C. with 50 psi(~0.35 MPa) of constant hydrogen pressure. After preconditioning thecatalyst separated from the working solution by decanting, and thereactor was recharged with a fresh 100 mL of EAQ working solution. Ahydrogenation reaction was effected at 50° C. as described the sectionabove titled “Stirred Tank Autoclave Reactions and Apparatus”.

Hydrogenation of EAQ was successful as evidenced by the working solutioncolor change from yellow to brown and consumption of hydrogen indicatedby a pressure change in the bottle of 18 psi (~ 0.12 MPa) following 10minutes of agitated shaking of the catalyst powder at 50° C. The finalEAQ conversion to EAQH₂ was 43.7%. The final productivity at terminationof reaction was 437 (based on H₂ moles consumed/ moles Pd metal).

Comparative Example 2

12.5 grams of 2 wt% Pd by weight on a SiO₂-Al₂O₃support -Type 429powdered catalyst from Johnson Matthey and 1250 mL of EAQ workingsolution were charged to an Autoclave Engineers 1 gallon (~3.79 L)HASTELLOY® C vessel, model number N6657HC. A hydrogenation reaction waseffected as described the section above titled “Stirred Tank AutoclaveReactions and Apparatus” using the standard pitched blade turbine with ametal disc stack and screens, but not including any immobilized catalystdiscs described above. Hydrogenation of EAQ was accomplished asevidenced by the working solution color change from yellow to brown atthe end of the test and consumption of hydrogen indicated by a pressurechange of 73.2 psi (~ 0.505 MPa) in the reactor monitored over 1 hour.

Following the test, the test fluid containing the slurried powdercatalyst was gravity filtered through a 0.7 µm micron pore rated glassfiber filter capsule (Sterlitech Corporation, Kent, WA). To accomplishthis test a 50-mL polyethylene luer syringe barrel without plunger(Terumo Medical Corporation, Somerset, NJ) was attached to the capsuleand 30 mL of the catalyst slurried in the post reaction working solutionwas added to the barrel. Effluent from the filter capsule was collectedin a 20-mL glass class a graduated cylinder. Volume was noted at timeintervals measured by a stop watch.

Results of this test are recorded plotted in terms of flow/area per unittime or filtration flux in FIG. 8 . These results show clearly that theworking solution and slurry particles rapidly clog the filter resultingin a decay to zero flux. In addition, and as shown in FIG. 8 , the useof the porous fibrillated polymer membranes to enmesh and immobilize thestructured catalyst particles resulted no filter clogging (InventiveExample 1) whereas the non-immobilized structured catalyst particlesclogged the filter (Comparative Example 1). Thus, ease of processing isvastly improved with the use of the expanded polymer matrices as thereis no need to change filters or to remove catalyst particles from thefilter. The final EAQ conversion to EAQH₂ was 81.1 %. The productivitywas not calculated since the catalyst was not first preconditioned toensure starting in a reduced state.

Comparative Example 3

Approximately 2.5 grams of 2 wt% Pd by weight on a SiO₂-Al₂O₃ support-Type 429 powdered catalyst from Johnson Matthey (Royston, UnitedKingdom) and 1000 mL of EAQ working solution were charged to a AutoclaveEngineers 1 gallon (~3.79 L) HASTELLOY® C vessel, model number N6657HC.A hydrogenation reaction was effected as described the section abovetitled “Stirred Tank Autoclave Reactions and Apparatus” using thestandard pitched blade turbine with a metal disc stack and screens, butnot including any immobilized catalyst discs described above. For thisthe reactor was brought to 55° C., pressurized to 200 psi (~1.38 MPa)with hydrogen, and stirring was initiated. Hydrogenation of EAQ wasaccomplished as evidenced by the working solution color change fromyellow to brown at the end of the test and consumption of hydrogenindicated by a pressure change in the reactor monitored over 1 hour.Upon completion of this test (referred to as “batch 1”) the catalystpowder was recovered and the reactor was cleaned as described in thesection above titled “Stirred Tank Autoclave Reactions and Apparatus”.At this point the reactor was charged with the recovered catalyst minusmaterial lost in the filtration of the working solution and in coatingof the apparatus (note this powder catalyst was removed by rinsing insubsequent solvent washing of the apparatus prior to the subsequentreaction run/batch - removal of catalyst was assessed visually until notpowder was visible - typically requiring about 3 liters of solvent (witha density of ~0.8 g/mL) to rinse per batch).

The reactor was then charged with a fresh 1000 mL of EAQ workingsolution and prepared as in the previous batch and the reactioncommenced resulting in another successful hydrogenation (termed “batch2”). Following batch 2 the same sequence was repeated for “batch 3” and“batch 4”, respectively. After all four batches respectively, thecatalyst powder was solvent rinsed and dried. The final weight of thecatalyst was approximately 1.9 grams suggesting a loss of approximately24% of the starting powder catalyst to filter trapping and transfer.

The EAQ conversion to EAQH₂ in the first batch was 28.5%. After 4batches 297.4 g of EAQH₂ were deemed to be produced based on hydrogenconsumption. The productivity after the first batch was 285 (based on H₂moles consumed/ moles Pd metal in the initial catalyst charge). Based onthe process described in Sheldon, R.A., Chem Ind, 12-15, 1997 theE-Factor (Mass Waste g/Mass Product) of 32.6 was calculated based ongrams of material waste generated (rinse and reaction solvent 12,000mL * 0.8 g/mL + catalyst 0.6 g) and the grams of product produced overfour batches.

Comparative Example 4

Approximately 2.0 grams of 2 wt% Pd by weight on a SiO₂-Al₂O₃ support-Type 429 powdered catalyst from Johnson Matthey (Royston, UnitedKingdom) and 1000 mL of limonene solution were charged to a AutoclaveEngineers 1 gallon (~ 3.79 L) HASTELLOY® C vessel, model number N6657HC.A reaction was effected by pressurizing the reactor to 50 psi (~0.35MPa) at a room temperature of 21° C. and initiating stirring at 350 rpmas described the section above titled “Stirred Tank Autoclave Reactionsand Apparatus” using the standard pitched blade turbine with a metaldisc stack and screens, but not including any immobilized catalyst discsdescribed above or any PVDF screens. Reaction was accomplished asevidenced by pressure change in the reactor monitored over 1 hour. Uponcompletion of this test (referred to as “batch 1”) the catalyst powderwas recovered and the reactor was cleaned as described in the sectionabove titled “Stirred Tank Autoclave Reactions and Apparatus”.

The reactor was then charged with the recovered catalyst minus materiallost in the filtration of the working solution and in coating of theapparatus (note this powder catalyst was removed by rinsing insubsequent solvent washing of the apparatus prior to the subsequentreaction run/batch - removal of catalyst was assessed visually until nopowder was visible - typically requiring about 3 liters of solvent (witha density of ~0.8 g/mL) to rinse per batch). The reactor was thencharged with a fresh 1000 mL of limonene working solution and preparedas in the previous batch and the reaction commenced resulting in anothersuccessful hydrogenation (termed “batch 2”). Following batch 2 the samesequence was repeated for “batch 3” and “batch 4”, respectively. Afterall four batches respectively, the catalyst powder was solvent rinsedand dried). The hydrogen consumption after batches 1, 2, 3, and 4 andwere measured to be 4.6 psi (~0.032 MPa), 4.5 psi (~ 0.031 MPa), 3.7 psi(~ 0.026 MPa), and 3.3 psi (~ 0.023 MPa); respectively. The productivityfor the first batch was not used as some of the hydrogen consumed mayhave gone to reducing the oxidized catalyst. The productivity for thesecond, third, and fourth batches respectively were 94.3, 77.5, and 67.1(based on H₂ moles consumed/ moles Pd metal in the initial catalystcharge). FIG. 10 shows the relative productivity with the respective2^(nd), 3^(rd), and 4th sequential batches. Based on the processdescribed in Sheldon, R.A., 1997, supra an E-Factor (Mass Waste g/MassProduct) of 382.4 was calculated based on grams of material wastegenerated (rinse and reaction solvent 9,000 mL * 0.8 g/mL) and the gramsof product produced over four batches.

Example 1

A composite of blend of 50 wt% PTFE and 50 wt% Type 429 Pd/SiO₂-Al₂O₃catalyst (2 wt% Pd) from Johnson Matthey (Royston, United Kingdom)having a size of approximately 14.5 µm was blended in a manner generallytaught in U.S Publication No. 2005/0057888 to Mitchell, et al. andsubsequently uniaxially expanded according to the teachings of U.S. Pat.No. 3,953,566 to Gore. The resulting porous fibrillated ePTFE membraneincluded supported catalyst particles enmeshed and immobilized withinthe ePTFE node and fibril matrix. The porous fibrillated ePTFE membranehad a thickness of 0.47 mm. The membrane was characterized by mercuryporosimetry to have an intrusion volume of 3.17 mL/g, resulting in atotal porosity of 86%, a total pore area of 133.25 m²/g, a bulk densityof 0.27 g/cm³, and a skeletal density of 1.9 g/cm³. 2.33 grams of thisporous fibrillated ePTFE membrane was then diced into 1 cm² squares(representing 0.0233 grams Pd metal content) and was charged into a 0.5L Parr glass bottle with 100 mL of EAQ working solution. Hydrogenationof EAQ was successful as evidenced by the working solution changingcolor from yellow to brown and consumption of hydrogen that wasindicated by a pressure change in the bottle of 27 psi (~ 0.19 MPa)following 10 minutes of agitated shaking of the catalyst powder at 50°C. The final EAQ conversion to EAQH₂ was 40.1%. The final productivityat termination of reaction was 400 (based on H₂ moles consumed/ moles Pdmetal).

Example 2

A composite of blend of 50 wt% PTFE and 50 wt% Type 429 Pd/SiO₂-Al₂O₃catalyst (2 wt% Pd) from Johnson Matthey (Royston, United Kingdom)having a size of approximately 14.5 µm was blended in a manner generallytaught in U.S Publication No. 2005/0057888 to Mitchell, et al. andsubsequently uniaxially expanded according to the teachings of U.S. Pat.No. 3,953,566 to Gore. The resulting porous fibrillated ePTFE membraneincluded supported catalyst particles enmeshed and immobilized withinthe ePTFE node and fibril matrix. The porous fibrillated ePTFE membranehad a thickness of 0.14 mm. The membrane was characterized by mercuryporosimetry to have an intrusion volume of 1.04 mL/g, resulting in atotal porosity of 65%, a total pore area of 68 m²/g, a bulk density of0.62 g/cm³, and a skeletal density of 1.77 g/cm³. The porous fibrillatedePTFE membrane comprising the supported catalyst particles was die cutinto discs and assembled into a disc stack as described above in thesection entitled “Formation of Disc Stack” with 16 discs and 15 PVDFspacers weighing a total of 25 grams.

The disc stack was attached to an impeller shaft, and 1000 mL of EAQworking solution were charged to a Autoclave Engineers (Parker AutoclaveEngineers, Erie, PA) 1 gallon (~3.79 liters) HASTELLOY® C vessel, modelnumber N6657HC. The reactor was charged to 200 psi (~ 1.38 MPa) andbrought to a temperature of 55° C. Stirring was initiated at 350 rpm. Ahydrogenation reaction was effected as described in detail in thesection titled “Stirred Tank Autoclave Reactions and Apparatus” using astandard pitched blade turbine (i.e., impeller) with the disc stackaffixed thereto. Hydrogenation of EAQ was accomplished as evidenced bythe working solution color change from yellow to brown at the end of thetest and consumption of hydrogen was indicated by a pressure change of40.7 psi (~ 0.281 MPa) in the reactor monitored over 1 hour.

Following the reaction, the test fluid containing the working solutionand reaction products were gravity filtered through a 0.7 µm glass fiberfilter capsule (Sterlitech Corporation). To accomplish this test, a50-mL polyethylene luer syringe barrel without plunger (Terumo MedicalCorporation) was attached to the capsule and 30 mL of the catalystslurried in the post reaction working solution was added to the barrel.Effluent from the filter capsule was collected in a 20-mL glass (classa) graduated cylinder. Volume was noted at time intervals measured by astop watch. Results are shown in the Table and plotted in terms offlow/area per unit time or filtration flux in FIG. 8 . The reactor afterproduct recovery was visibly clean. In contrast to the non-immobilizedcatalyst, the filter was not clogged and continued to flow. The finalEAQ conversion to EAQH₂ was determined to be 45%. The productivity wasnot calculated since the catalyst was not first preconditioned to ensurestarting in a reduced state.

TABLE Example Comparative Form Description Inventive Form SystemAgitation # of Batches considered for productivity Comparative ExampleProductivity (moles product/ moles Pd) Inventive Example Productivity(moles product/ moles Pd) Comparative Example E Factor (g waste/ gproduct) Inventive Example E Factor (g waste/ g product) 1 PowderImmobilized Catalyst Pieces EAQ Shaken 1 437 401 NA NA 2 PowderImmobilized Catalyst Discs EAQ Stirred 1 285 312 32.6 4.9 4 PowderImmobilized Catalyst Discs Limonene Stirred 3 335 547 542.9 0.0003

Example 3

A composite of blend of 50 wt% PTFE and 50 wt% Type 429 Pd/SiO₂-Al₂O₃catalyst was (2 wt% Pd) from Johnson Matthey (Royston, United Kingdom)having a size of approximately 14.5 µm was blended in a manner generallytaught in U.S. Publication No. 2005/0057888 to Mitchell, et al. andsubsequently uniaxially expanded according to the teachings of U.S. Pat.No. 3,953,566 to Gore. The resulting porous fibrillated ePTFE membraneincluded supported catalyst particles enmeshed and immobilized withinthe ePTFE node and fibril matrix. The porous fibrillated ePTFE membranehad a thickness of 0.47 mm. The membrane was characterized by mercuryporosimetry to have an intrusion volume of 3.17 mL/g, resulting in atotal porosity of 86%, a total pore area of 133.25 m²/g, a bulk densityof 0.27 g/cm³, and a skeletal density of 1.9 g/cm³. The porousfibrillated ePTFE membrane comprising the enmeshed immobilized supportedcatalyst particles was die cut into discs and assembled into a discstack with die cut PVDF Scrim spacers as described above in the sectionentitled “Formation of Disc Stack” with 5 discs of expanded tape and 4PVDF spacers weighing a total of 4.5 grams.

The disc stack was attached to an impeller shaft, and 1000 mL of EAQworking solution were charged to a Autoclave Engineers 1 gallon (~ 3.79liters) HASTELLOY® C vessel, model number N6657HC. The reactor wascharged to 200 psi (~ 1.38 MPa) and brought to a temperature of 50° C. Ahydrogenation reaction was effected as described in detail in thesection above titled “Stirred Tank Autoclave Reactions and Apparatus”using a standard pitched blade turbine (i.e., impeller) with the discstack affixed thereto. Hydrogenation of EAQ was accomplished asevidenced by the working solution color change from yellow to brown atthe end of the test and consumption of hydrogen was indicated by apressure change of 18.7 psi (~ 0.129 MPa) in the reactor monitored over1 hour.

Upon completion of this test (referred to as “batch 1”) the catalystpowder was recovered and the reactor was cleaned as described in detailin the section titled “Stirred Tank Autoclave Reactions and Apparatus”.The disc assembly was then rinsed with solvent (1 L to remove anyhydrogenated EAQ which would form unstable peroxides on contact withair). The working solution was then filtered to capture any lostcatalyst. Catalyst loss was determined to be minimal and within solventhold up or drying changes for the filter paper (~ 0.01 g). The reactorwas also observed to be visibly clean. The rinsed disc stack catalystwas charged to the reactor and a new 1000 mL portion of EAQ workingsolution and prepared as in the previous batch.

The hydrogenation reaction was then commenced resulting in anothersuccessful hydrogenation (termed “batch 2”). Following batch 2 the samesequence was repeated for “batch 3” and “batch 4”, respectively (thesame rinse solvent for the disc stack was used in all 4 tests). FIG. 9shows the reactor pressure rate versus time for the first run. The EAQconversion to EAQH₂ in the first batch was determined to be 31.2%. After4 batches, 228.4 g of EAQH₂ were deemed to be produced based on hydrogenconsumption. The productivity after the first batch was 312.4 (based onH₂ moles consumed/ moles Pd metal in the initial catalyst charge). Basedon the process described in Sheldon, R.A., 1997, supra an E-Factor of4.7 Mass Waste g/Mass Product was calculated based on grams of materialwaste generated (rinse and reaction solvent 1,000 mL * 0.8 g/mL) and thegrams of product produced over four batches. The E factor of theimmobilized structured catalyst particles is far superior tonon-immobilized structured catalyst particles as demonstrated in thereduction of waste. In particular, the reduction in waste was 6.7 foldbetter in this Example compared to Comparative Example 3.

Example 4

A composite of blend of 50 wt% PTFE and 50 wt% Type 429 Pd/SiO₂-Al₂O₃catalyst (2 wt% Pd) from Johnson Matthey (Royston, United Kingdom)having a size of approximately 14.5 µm was blended in a manner generallytaught in U.S. Publication No. 2005/0057888 to Mitchell, et al. andsubsequently uniaxially expanded according to the teachings of U.S. Pat.No. 3,953,566 to Gore. The resulting porous ePTFE membrane includedsupported catalyst particles enmeshed and immobilized within the ePTFEnode and fibril matrix. The porous ePTFE membrane had a thickness of0.47 mm. The membrane was characterized by mercury porosimetry to havean intrusion volume of 3.17 mL/g, resulting in a total porosity of 86%,a total pore area of 133.25 m²/g, a bulk density of 0.27 g/cm³, askeletal density of 1.9 g/cm³. The porous fibrillated ePTFE membranecontaining immobilized catalyst was die cut into discs and assembledinto a disc stack as described above in the section entitled “Formationof Disc Stack” with 5 discs weighing a total of 4.0 grams. The discstack was then attached to an impeller shaft.

1000 mL of limonene working solution was charged to an AutoclaveEngineers 1 gallon HASTELLOY® C vessel, model number N6657HC. Thereactor was charged to 50 psi (~ 0.34 MPa) and brought to a temperatureof 21° C. Stirring was initiated at 350 rpm. A hydrogenation reactionwas effected as described in detail in the section above titled “StirredTank Autoclave Reactions and Apparatus” using a standard pitched bladeturbine (i.e., impeller) with the disc stack affixed thereto. Thereaction was accomplished as evidenced by pressure change in the reactormonitored over 1 hour.

Upon completion of this test (referred to as “batch 1”) the catalystpowder was recovered and the reactor was cleaned as described in detailin the section above titled “Stirred Tank Autoclave Reactions andApparatus” using a standard pitched blade turbine (i.e., impeller) withthe disc stack affixed thereto. At this point the working solution withreactants and products were removed from the reactor and processed byvacuum filtration. The reactor appeared visually clean and so was deemedready for the next batch. To accomplish reaction of the next batch thereactor was then charged with a fresh 1000 mL of limonene workingsolution and prepared as in the previous batch and the reactioncommenced resulting in another successful hydrogenation (termed “batch2”). Following batch 2 the same sequence was repeated for “batch 3” and“batch 4”, respectively.

The recovered working solution was filtered and dried and each of thefour batches. The hydrogen consumption after batches 1, 2, 3, and 4 andwas 8 psi (~ 0.06 MPa), 6.3 psi (~ 0.043 MPa),6 psi (~ 0.04 MPa), and5.8 psi (~0.04 MPa), respectively. The productivity for the first batchwas not used as some of the hydrogen consumed may have gone to reducingthe oxidized catalyst. The productivity for the second, third, andfourth batches, respectively, were 132,125, and 121 (based on H₂ molesconsumed/ moles Pd metal in the initial catalyst charge). FIG. 10 showsthe relative productivity with across batches 2-4, respectively of thisExamples versus Comparative Example 4. As shown in FIG. 10 , thestructured catalyst particles immobilized in the porous fibrillatedpolymer membrane demonstrated greater productivity than thenon-immobilized structured catalysts. Based on the process described inSheldon, R.A., 1997, supra an E-Factor (Mass Waste g/Mass product g) of0.0006 Mass Waste g/Mass Product was calculated based on grams ofmaterial waste generated (0.01 g catalyst lost) and the 17.7 grams ofproduct produced over four batches. The E factor of the immobilizedstructured catalyst particles is far superior to non-immobilizedstructured catalyst particles as demonstrated in the reduction of waste.In particular, the reduction in waste was 1.8 million fold better inthis Example compared to Comparative Example 4.

Example 5

A composite of blend of 50 wt% PTFE and 50 wt% Type 429 Pd/SiO₂-Al₂O₃catalyst (2 wt% Pd) from Johnson Matthey (Royston, United Kingdom)having a size of approximately 14.5 µm was blended in a manner generallytaught in U.S. Publication No. 2005/0057888 to Mitchell, et al. andsubsequently uniaxially expanded according to the teachings of U.S. Pat.No. 3,953,566 to Gore. The resulting porous ePTFE membrane includedsupported catalyst particles enmeshed and immobilized within the ePTFEnode and fibril matrix. The porous fibrillated ePTFE membrane had athickness of 0.14 mm. The membrane was characterized by mercuryporosimetry to have an intrusion volume of 1.04 mL/g, resulting in atotal porosity of 65%, a total pore area of 68 m²/g, a bulk density of0.62 g/cm³, and a skeletal density of 1.772 g/cm³. The porousfibrillated ePTFE membrane was then formed onto supported tubes,bundled, sealed in a reactor, and then inserted into the apparatusdescribed in detail above in the section titled “Continuous LoopReactions in a Packed Tubular Array”.

The reactor apparatus was charged, prepared for reaction, and thereaction was commenced as described in “Continuous Loop Reactions in aPacked Tubular Array” set forth above. After operation for 2 hours, theconcentration of EAQH₂ based on the titrated extracted H₂O₂ was 0.09moles/L, corresponding to a conversion of 36% of the EAQ material with aproductivity of 239. During the course of the 2 hour experiment, theworking solution was recirculated through the reactor 582 times,suggesting a conversion of 0.06% per pass. This Example demonstratesthat porous fibrillated polymer membrane may be used in a continuousflow reaction.

Example 6

In this example, experiments were conducted as described in Example 5with the exception that a second tube array reactor containing the samematerial was added directly below the first reactor in series such thatthe working solution and gas bubbles flowed through the two arrays inseries. After operation for 2 hours, the concentration of EAQH₂, basedon the titrated extracted H₂O₂ was 0.16 moles/L; corresponding to aconversion of 50% of the EAQ material with a productivity of 424.

During the course of the 2 hour experiment, the working solution wasrecirculated through the reactor 582 times, suggesting a conversion of0.09% per pass. This example demonstrates that the degree ofhydrogenation in the flow reactor can be simply scaled or tailored toproduce a product of desired conversion by the number of units in seriesor by altering the contact time with the immobilized supported catalystparticle. This Example demonstrates that porous fibrillated polymermembrane may be used in a continuous flow reaction in series.

Example 7

A composite of blend of 50 wt% PTFE and 50 wt% Pd/C catalyst (5 wt% Pd;Alfa Aesar PN A102023-5) was blended in a manner generally taught inU.S. Publication No. 2005/0057888 to Mitchell, et al. to form aPTFE/catalyst mixture and subsequently passed through calendar rolls.The resulting porous ePTFE membrane included supported catalystparticles enmeshed and immobilized within the ePTFE node and fibrilmatrix. The porous fibrillated ePTFE membrane had a thickness of 0.14mm. The membrane was characterized by mercury porosimetry to have anintrusion volume of 1.04 mL/g, resulting in a total porosity of 50%, atotal pore area of 120 m²/g, a bulk density of 1.12 g/cm³, and askeletal density of 2.25 g/cm³.

1.12 grams of the porous fibrillated ePTFE membrane was then diced into1 cm² squares (representing 0.02818 grams Pd metal content) and then wascharged into a 0.5-L Parr bottle with 100 mL of s-limonene.Hydrogenation of s-limonene was successful as evidenced by consumptionof hydrogen indicated by a pressure change in the bottle of 25 psi (~110 kPa) following 10 minutes of agitated shaking of the catalyst powderat 25° C. The final limonene conversion was determined to be 4.5%(conversion was moles of product produced based on moles H₂ consumedbased on pressure change divided by moles limonene starting material inthe reactor x100). This example demonstrates that different supportedcatalyst particles may be enmeshed in the fibrillated polymer membraneand used in a different hydrogenation reaction.

Example 8

A composite blend of 70 wt% polytetrafluoroethylene (PTFE) and 30 wt%5R452 Pd/C catalyst (the Pd/C supported catalyst was 5% Pd by weight)from Johnson Matthey (Royston, United Kingdom) was produced via aco-coagulation as is generally known in the art.

The composite blend material was then uniaxially expanded on a heatedpantograph. The resulting expanded composite had a thickness of 0.74 mm.The expanded composite was characterized by mercury porosimetry to havean intrusion volume of 0.74 mL/g, resulting in a total porosity of60.0%, a total pore area of 60.9 m²/g, a bulk density of 0.82 g/cm³, anda skeletal density of 2.04 g/cm³. 0.1 grams of the expanded compositewas then diced into 1 cm² squares (representing 0.05 grams Pd metalcontent) and was charged into a 1 L MP 06 RC1 Pressure stirred reactorwith a gassing impeller (Mettler Toledo, Columbus, Ohio, USA) having aBuchiglasuster BPC pressure/ hydrogen flow control and measurementsystem (Buchiglasuster, Uster, Switzerland) with 35 grams ofnitrobenzene dispersed in 400 mL of methanol. The reactor was purged andpressurized to 3 barg (~ 300 kPa), set to a temperature of 30° C. usinga recirculating water jacket and temperature controller. Hydrogenationof Nitrobenzene to Aniline was successful based on gas consumptionmeasured by the BPC proportional to 0.023 moles of hydrogen at the settemperature and pressure. Following the experiments, separate GC/MS andNMR measurements confirmed Aniline had been produced in agreement withthe hydrogen gas consumption.

Example 9

A composite blend of 70 wt% polytetrafluoroethylene (PTFE) and 30 wt%5R452 Pd/C catalyst (the Pd/C supported catalyst was 5% Pd by weight)from Johnson Matthey (Royston, United Kingdom) blended in a mannergenerally taught in U.S Publication No. 2005/0057888 to Mitchell, et al.and subsequently uniaxially expanded according to the teachings of U.S.Pat. No. 3,953,566 to Gore.

The resulting expanded composite had a thickness of 0.544 mm. Theexpanded composite was characterized by mercury porosimetry to have anintrusion volume of 0.84 mL/g, resulting in a total porosity of 62.2%, atotal pore area of 62.1 m²/g, a bulk density of 0.74 g/cm³, and askeletal density of 1.97 g/cm³. 0.1 grams of this composite was thendiced into 0.5 to 1 cm² squares (representing 0.05 grams Pd metalcontent) and was charged into a 1 L MP 06 RC1 Pressure stirred reactorwith a gassing impeller (Mettler Toledo, Columbus, Ohio, USA) having aBuchiglasuster BPC pressure/ hydrogen flow control and measurementsystem (Buchiglasuster, Uster, Switzerland) with 35 grams ofnitrobenzene dispersed in 400 mL of methanol. The reactor was purged andpressurized to 3 barg (~ 300 kPa), set to a temperature of 30° C. usinga recirculating water jacket and temperature controller. Hydrogenationof Nitrobenzene to Aniline was successful based on gas consumptionmeasured by the BPC proportional to 0.025 moles of hydrogen at the settemperature and pressure. Following the experiments separate GC/MS andNMR measurements confirmed Aniline had been produced in agreement withthe hydrogen gas consumption.

The invention of this application has been described above bothgenerically and with regard to specific embodiments. It will be apparentto those skilled in the art that various modifications and variationscan be made in the embodiments without departing from the scope of thedisclosure. Thus, it is intended that the embodiments cover themodifications and variations of this invention provided they come withinthe scope of the appended claims and their equivalents.

What is claimed is:
 1. A continuous flow reaction system for multiphasereactions having at least three phases, said reaction system comprising:a catalytic article comprising a porous fibrillated polymer membranethat includes supported catalyst particles durably enmeshed within theporous fibrillated polymer membrane, said catalytic article being in theform of diced tape; a liquid phase comprising at least one liquid phasereactant; a gas phase comprising at least one gas phase reactant; and areaction vessel in the form of a continuous loop and being configuredfor continuous flow of the liquid phase reactant and the gas phasereactant across and through the catalytic article.
 2. The reactionsystem of claim 1, wherein the catalytic article is not configured as acontactor.
 3. The reaction system of claim 1, wherein the reactionsystem is configured for hydrogenation.
 4. The reaction system of claim1, wherein the porous fibrillated polymer membrane is insoluble toreactants and products in the multiphase chemical reaction.
 5. Thereaction system of claim 1, wherein the porous fibrillated polymermembrane comprises polytetrafluorethylene (PTFE),poly(ethylene-co-tetrafluoroethylene) (ETFE), ultra-high molecularweight polyethylene (UHMWPE), polyparaxylylene (PPX), polylactic acidand any combination or blend thereof.
 6. The reaction system of claim 1,wherein the porous fibrillated polymer membrane comprisespolytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene(ePTFE), modified PTFE, or a PTFE copolymer.
 7. The reaction system ofclaim 1, wherein the porous fibrillated polymer membrane comprisesexpanded polytetrafluoroethylene (ePTFE).
 8. The reaction system ofclaim 1, wherein the porous fibrillated polymer membrane has a porosityfrom about 30% to about 95%.